Improved steam-boiler



Nirnn ArtNr FFicE.

BENJAMIN F. CAMPBELL, OF ROXBURY, MASSACHUSETTS.

IIVIPROVED STEAM-BOILER.

Specification forming part of Letters Patent No. 30,957, dated December18, 1860.

companying drawings, making part of this,

specification, in which- Figure l is a view of my improved boiler; Fig.2, a longitudinal vertical section; Fig. 3, a transverse verticalsection on the line c :n of Fig. 2.

The object of my present invention is to produce a steam-boiler having'alarge amount I of heating-surface in a compact form, and which shallproduce a good combustion of the fuel, thus rendering it economical inits operation; and my invention consists in a steam-boiler, from thebody of which projects laterally wings containing series of fire-tubescommunicating with the iire-boX and with a smoke-stack.

That others skilled in thc art may understand and use my invention, Iwill proceed to describe the manner in which I have carried out thesame.

In the said drawings, A is the vertical body of the boiler, the lowerpart of which contains the grate and iire-boX B, which is surroundedwith a water-space, C. The upper part of this body forms a steam-dome,D, to which access may be had for repairs, dsc., through a man-hole, c,on top. (The steampipes, valves, itc., not essential to theunderstanding of my invention, are not shown on these drawings.) A door,b, gives access to the iire-boX B. From opposite sides of the body A ofthe boiler project wings E, which are circular in their cross-section,as shown in Fig. 3, and are connected to the circular body A at c. Acrown-sheet, F, projects inward into the {ire-space B on each side, andfrom it rises a tube-sheet, G, which is attached to 'anothercrown-sheet, H, over the centerof the fire-box B. The tubes I aresecured at their inner ends in the tube-sheets G, and at their otherends in the heads K of each of the wings E. As the space between the twotubesheets G is considerably less than the diameter of the lower part ofthe fire-box B, the

strain which would be put upon the crown-` sheet by the heat of thefire, if in one plain surface, is divided, the crown-sheets F beingbridged by the tube-sheets G, while the crownsheet H, which iscomparatively narrow, may be braced from the top of the dome D. Inorder, however, to give additional support to the crown-sheets F, Iplace over each a bridge, L, which is a heavy plate or sheet of ironperforated with holes through which the tubes I pass, the holes beinglarge enough for the water to circulate around the tubes. The lower edgeof this plate L is slit up a short distance at intervals, and thealternate portions ofthe plate are bent toward opposite sides, formingfeet e, which are riveted to the top of the crown-sheet. y

This construction of bridge I iind possesses great strength, while itallows me to place the lower row of tubes I close down to the crownsheetF. The water-space C around the lireboX communicates with the waterspace around the tubes I in each wing E, and these latter spaces opendirectly into the dome D, the water-level being maintained a littleabove the crown-sheet H. The heads K of the Wings E are each intended toform one side of a smoke-box, into which the cylinder exhausts.

These smoke-boxes may each have a separate smoke-stack; or a iiue fromeach may enter a single smoke-stack, as may be found most convenient.The boiler here represented possesses the advantages of compactness,cheapness of construction, and great strength. The weight may be equallybalanced on each side of the fire-box, and its combustion of fuel isfound to be very perfect.

I am aware of steam-boilers having been constructed with the tubes and-tube-sheet projected from one side of the fire over the grate, as inthe1 boiler upon which Letters Patent were granted to C. F. Thomas, June19, 1855. I therefore disclaim the projection of the tube and tube-sheetover the iire; but

What I do claim as of my invention isl. The combined arrangement of twowings, E, containing the tubes I, with a single fireboX, when the saidwings project equally from either side of the fire-chamber over thegrate, as and for the purposes hereinbefore set. forth.

2. The perforated plate L for bridging the crown-sheet F, substantiallyas set forth.

B. F. CAMPBELL.

Witnesses:

THos. R. RoAcH, Trios. D. GLovEn.

